Asynchronous Operations with Promises

Asynchronous operations in Organiq are handled with Promises, rather than the more traditional Node.js-style callbacks.

A traditional asynchronous method implemented with callbacks might be called like:

object.doAsyncOperationWithCallback(function(err, res) {
    if (err) { /* failure */ }
    else { /* success */ }
});

When implemented with promises, we would have instead something like:

object.doAsyncOperationWithPromise()
    .then(function(res) { /* success */ },
          function(res) { /* failure */ }) /* optional failure function */

Not much of a difference in trivial examples, but promises tend to simplify error handling and chaining lots of nested asynchronous network operations.

Internally and in the example programs, Organiq uses the when.js library for handling promises. It's simple and small and works on Tessel.

You will encounter promises when:

• Using APIs such as organiq.getDevice and Device.sync
• Writing asynchronous methods and property getters as part of device implementations
• Invoking remote methods on Device objects from external applications

For the most part, all you need to know to use asynchronous methods in Organiq is to use the .then syntax as in the example above.